1. Field of the Invention
The invention relates to a data writing method and writing device, and more particularly to a data writing method and writing device for an electronic erasable read only dynamic memory in an electronic device.
2. Description of the Related Art
FIG. 1 illustrates a game controller for a game apparatus (not shown). The game controller includes a main control device 9, and an expansion device 7. The main control device 9 includes a core unit 90, an electronic erasable read only dynamic memory (EEPROM) 91 stored with program data and connected electrically to the core unit 90, and an expansion connector 92 connected electrically to the core unit 90. The expansion device includes a subunit 70, and a connector 71 connected electrically to the subunit 70. The expansion connector 92 and the connector 71 have the same interface. The connector 71 is optionally connected to the expansion connector 92 if necessary.
The EEPROM 91 has a plurality of pins, such as WP, VDD, GND, SCL and SDA. The core unit 90 outputs a write-protection voltage to the WP pin, and outputs a system voltage to the VDD pin. The core unit 90 controls The EEPROM 91 using the write-protection voltage and the system voltage to operate in a write state or a read/write-protection state. That is, when the write-protection voltage is smaller than the system voltage, the EEPROM 91 is in the write state. Otherwise, the EEPROM is in the read/write-protection state. When the EEPROM 91 is in the write state, the core unit 90 is operable to rewrite updated data into the EEPROM 91.
The interface of each of the expansion connector 92 and the connector 71 includes VCC, GND, SCL and SDA terminals. As a result, if the program data in the EEPROM 91 needs to be upgraded or updated, the EEPROM 91 must be sent back to the original fabrication company to record new firmware data. Alternatively, updating firmware is carried out by execution of a software program installed in a computer device and provided by the original fabrication company. Therefore, data writing for the EEPROM 91 is inconvenient.